Process and apparatus for transferring indicia



Oct. 14, 1969 A. LYTHGOE PROCESS AND APPARATUS FOR TRANSFERRING INDICIA Filed Oct. 21-, 1965 United States Patent 3,472,719 PROCESS AND APPARATUS FOR TRANSFERRING INDICIA Alan Lennox Lythgoe, London, England, assignor to Letraset Limited, London, England, a British company Filed Oct. 21, 1965, Ser. No. 499,687 Claims priority, application Great Britain, Oct. 30, 1964, 44,384/ 64; May 14, 1965, 20,497/ 65 Int. Cl. B44c 3/02, N16 US. Cl. 156-236 13 Claims ABSTRACT OF THE DISCLOSURE In a transfer material having indicia on a carrier sheet with an adhesive either applied over or present in the indicia, the bond between indicia and carrier sheet is weakened or broken without separating indicia from carrier sheet by passing the carrier sheet over an edge or small-radius surface or the carrier sheet is locally stretched at the indicia position, to facilitate transfer thereafter by application of pressure to the rear face of the carrier sheet.

This invention relates to processes for the application of indicia to successive receptor surfaces by the use of transfer materials, to apparatus for use in such processes and to transfer materials for use in such processes.

Transfer materials are known which comprise a carrier sheet, a plurality of ink indicia on said carrier sheet and an adhesive which is either present in the ink indicia or is applied over the indicia and, in that case, usually overlaps onto the carrier sheet. It is known that, by a suitable correlation of the physical and chemical characteristics of the carrier, the ink and the adhesive, it may be arranged that when the transfer material is laid with its adhesive face in contact with a receptor sheet and pressure is applied to the rear face of the carrier sheet in the region of an indicium, the indicium will leave the carrier sheet and become adherent to the receptor sheet, a transfer of the indicium thus being effected.

In a particularly valuable form of transfer sheet as aforesaid, described in British patent specification No. 959,670, it is arranged that by local stretching of the carrier sheet the bond between an indicium and the carrier sheet may be weakened or broken, thus enabling the indicium to become adherent to the receptor sheet under the action of an adhesive which, in its action, does not have to everwhelm the bond between indicium and carrier sheet because that bond is already weakened or broken. It is explained in the said specification that such a localised stretching of the carrier sheet may be effected by rubbing the rear face of the carrier sheet with a stylus or like device.

In the present invention use is made of transfer materials which comprise essentially a carrier sheet and ink indicia printed on said sheet, the physical characteristics of the ink and the carrier sheet being so mutually selected as to provide release of an indicium from the carrier sheet by the action of stretching the carrier film, for example by drawing the carrier sheet over an edge or surface of small radius or over a serrated surface in pressure contact with such surface, in each case with the rear face of the material nearer to that edge or surface and the front face (carrying the indicia) remote from that edge or surface or by exerting tension in the carrier film, e.g. by passing it between successive rolls driven at different speeds.

According to the present invention there is provided a process for the application of indicia to successive re- See ceptor surfaces, which comprises withdrawing from a reel a transfer tape which consists essentially of a tape support carrying ink indicia successively printed along its length, the physical characteristics of the support and the ink being so mutually selected as to provide release of an indicium from the support by the action of drawing the tape over an edge or surface of small radius or over a serrated surface in pressure contact with such surface, in each case with the rear face of the tape nearer to the said edge or surface and the front face carrying the indicia remote from that edge or surface, or by exerting tension in the tape support, or by a combination of any of these methods, causing the tape so withdrawn to pass over an edge or surface as aforesaid or to be subjected to tension as aforesaid, and adhering the successive indicia so released to successive receptor surfaces.

According to a still further feature of the invention there is provided a dispenser for transfer tape as aforesaid which comprises means for holding a reel of transfer tape, means for withdrawing tape from the reel and means associated therewith, comprising an edge or surface of small radius or a serrated surface so located that the tape on said withdrawal is caused to pass over said edge or surface of small radius making a substantial change of direction thereat, or over said serrated surface in pressure contact therewith. The transfer material of the present invention may have an adhesive in the indicia or covering the indicia or such an adhesive may be applied to the tape following the release of the indicia or may be applied to the surfaces to which the released indicia are to be adhered. Where the adhesive is already present on or in the indicia it is preferably nontacky but capable of being activated by pressure, by heat or by the action of a solvent. In the case of a pressure-sensitive adhesive the activation is effected by pressing the indicium onto the receptor surface. In the case of a heat-sensitive adhesive it may be arranged that the tape after the release of the indicia passes by a source of infra-red radiation with the effect of softening and thus activating the adhesive. In the case of a solvent-activated adhesive th solvent may be sprayed onto the adhesive at a stage following the release of the indicia, or may be applied to the receptor surface.

In the case where the adhesive is a pressure-sensitive adhesive it is preferably applied as a covering to the ink indicia rather than included in the ink indicia since it is found that the inclusion of a pressure-sensitive adhesive in the ink indicia makes it more difficult so to formulate the ink that the indicia will be readily released from the carrier tape by the methods indicated above. On the other hand heat-sensitive and solvent activated adhesives may readily be included in the ink used for the indicia if desired.

The operation of passing the transfer material over the edge or surface as aforesaid, since it releases the indicia from the carrier sheet or tape before the indicia are applied to a receptor surface is referred to herein as prerelease. It is to be understood however that this term does not imply that the indicia fall away from the carrier sheet; they may, and usually will, be held lightly in position 'by an overlapping adhesive layer or even, with certain carriers, by electrostatic forces.

The pre-release feature is achieved by selection of carrier base and ink in combination to provide an adequate bond between carrier and ink for normal handling but a bond incapable of withstanding the stresses set up during the pre-release operation. It will thus be appreciated that the ink must be formulated in specific relation to any given carrier base.

The carrier base may be in the form of a self-supporting film or may 'be a coated sheet material. The surface condition of the carrier is not critical in itself as variation in this characteristic can be catered for by varying the ink formulations to provide for pre-release of the indicia.

The carrier sheet or the surface of the carrier sheet may consist of a polymer or copolymer, e.g., a polymer or copolymer selected from polystyrene and polystyrene homologues and substituted polymers including high impact polystyrene, polystyrene with rubbery additives such as butadiene as comonomer, polystyrene butadiene acrylonitrile copolymer, acrylic polymer such as polymethyl methacrylate and other alkyl methacrylates, acrylic polymers with other polymers or comonomers such as butadiene and acrylonitrile, vinyl polymers including vinyl chloride, esters, acetals and alcohols and copolymers and with other polymers and comonomers, cellulose esters and ether, polycarbonates rubber hydrochloride, polyolefins such as polyethylene of normal and high density and polypropylene, polyesters, polyamides and gelatine. Other suitable carrier sheets are cellulose materials of all types including those of natural origin such as paper or cardboard. 'Regenerated celluloses, metal foils of all types, including those such as tin, zinc, steel, copper, silver, aluminium, gold, paper laminates of polymers and copolymers, waxes, resinous materials, glue, starch and casein, and paper coated with such .materials as silicones, or aluminium or chromium complexes, may all be used.

The indicia preferably consist of an organic polymer which may also contain plasticisers, dyes, pigments, stabilizers and fillers. Suitable polymers are cellulose nitrate; cellulose acetate; cellulose acetobutyrate; ethyl cellulose; ethylhydroxyethyl cellulose; dry oils and dry oil varnishes; alkyds and alkyds modified or copolymerised with a drying oil, styrene, urethane, vinyl, silicone or acrylic resin; polyvinyl halides, esters acetals and alcohols; polyurethanes; epoxy polymers; epoxyphenolic, polyamide epoxypolyamide and catalysed epoxy resins and copolymers; urea-, melamine-, and benzoguanamine-formaldehyde polymers; chlorinated and isomerised rubber; polystyrene and polyvinyl toluene; polysiloxanes and silicone containing polymers; polyacrylates, polymethacrylates and thermosetting acrylic resins; gelatin; zein; casein, starch or modified starch.

The above polymers are applied to the carrier sheet preferably in the form of a layer of viscous liquid such as a lacquer, i.e., a solution in organic solvents, or an aqueous emulsion, hot melt, plastisol, organosol or as a liquid monomer or liquid polymer containing catalyst. Various printing processes may be used such as screen process, fiexographic or gravure printing. The liquid indicia are then dried or set. If the lacquer contains a solvent said solvent should be selected to have no solvent effect on the carrier which could irreversibly key the indicia to the carrier.

The indicia are formulated to provide the necessary specifications of barrier properties, tensile strength, elongation and adhesion to the carrier sheet. Tensile strength is mainly determined by the polymer used and to a less extent by the plasticiser concentration; elongation is also determined mainly 'by the polymer and the amount of plasticiser; mutual adhesion between carrier sheet and indicia is determined by the polymers used for both the carrier sheet and indicia and also by the plasticiser concentration of the latter, a high plasticiser concentration giving more adhesion than a low plasticiser concentration by reducing the stretch-free properties. The same chemical class of polymer is preferably not used for the carrier sheet and the indicia since strong specific adhesion forces may be produced.

The pigments, dyes, fillers and stabilisers which may be incorporated in the transferable layer have a moderate effect on tensile strength, elongation and adhesion which must be allowed for. The tensile strength of the indicia is dependent on its thickness and this is also controlled.

Pressure sensitive adhesives are generally based on resin or polymer materials. An intrinsically tacky polymer or elastomer may be controlled as to tack by the addition of a tacky or non-tacky resin or plasticiser. Suitable polymers and tackifying materials are as follows: natural unvulcanised rubber, vulcanised rubber, synthetic rubber such as polyisobutylene, polychloroprene, polybutadiene, polyacrylonitrile and copolymers of these and with styrene and styrene homologues and acrylic monomers; polyvinyl alkyl ethers such as methyl, ethyl and butyl ethers; acrylic and methacrylic polymers such as polybutyl acrylate and copolymer with polybutyl methacrylate. Tacky and tackifying resins consist of rosin and rosin derivatives such as hydrogenated rosin, esters and alcohols; liquid polymeric styrenes and styrene homologues; polymerised terpenes such as beta-pinene; ketone resins; low molecular weight polyisobutylenes and other olefins.

If required, a tack controlling agent may be added, preferably in the form of a soft or easily deformable material to allow good flow and contact with the receiving surface. Particularly suitable materials are long chain hydrocarbons containing 12 or more carbon atoms such as paraffin and microcrystalline wax, polyethylene waxes, fatty acids and their derivatives such as metal salts, esters, alcohols, amides, nitriles and amines and particularly fatty acid mono or polyesters of polyols and polyethylene glycols and fatty alcohol ethers of polyethylene glycols; polyethylene glycols and polypropylene glycols.

It is usually convenient to provide a protective sheet which lies over the adhesive side of the transfer material, e.g., a tape of such protective sheet material may be interwound with a tape of the transfer material on a reel. Any tendency for indicia to transfer prematurely from the transfer material to the rear face of an adjacent sheet or coil of transfer material is thus prevented. Of course the protective sheet must be such that the adhesive present on the transfer material will not bond to it.

Suitable protective sheets may consist of a support sheet to which is applied a release material to provide the required low adhesion values to the adhesive layer. Suitable support sheets are cellulosic materials such as kraft paper, glassine paper and vegetable parchment paper. Suitable release materials are fatty acid chromium complexes of siloxanes such as polymethyl-siloxanes. The siloxane is preferably obtained by applying a reactive material to the support which polymerises or copolymerises with the support sheet to provide a siloxane which is insoluble, nonmigratory and strongly adherent and therefore does not affect the adhesive properties of the adhesive layer by migration into the adhesive or transfer onto the adhesive. For example, suitable reactive materials are methyl hydrogenpolysiloxanes, a metal salt catalyst being useful as a catalyst to accelerate polymerisation, and the materials may be applied as fluids, solution in organic solvents or aqueous emulsions.

The following examples will serve to illustrate the inventron:

Example 1 acetate (33% solids) 125 Castor oil glyceryl sebacate (72%) 25.5 Dimethyl cyclohexyl adipate 2.5

Titanium dioxide (rutile) 60 The printing is carried out by screen process to give a dry ink thickness of about 0.0005.

There is then applied an overall coating of a low tack pressure sensitive adhesive formulated as follows:

Parts Terpene resin (melting point in the range 8S C.) in the form of a 50% emulsion 37.3

Polyvinyl butyl ether (K values between 10-65) in the form of a 60% emulsion 37.3

Parts Copolymer of butyl acrylate and methyl acrylate in the form of a 50% emulsion 11.86 Methyl cellulose in solution in water 12.58 Water soluble flow agent (20 M) 0.96

A protective backing sheet consisting of silicone coated vegetable parchment is applied over the adhesive surface and is removed before use.

The indicia transferred to a receptor surface, can be improved in respect of hardness and adhesion by:

Action of heat-Fusion of the adhesive constituents occurs at about 100-120 C. rendering the indicia more firmly adherent and of greater resistance to abrasion.

Referring to the foregoing Example the following points should be observed:

(a) The ink formulation may be variable in respect of the castor oil glyceryl sebacate and dimethyl cyclohexyl adipate contents, such adjustments being dictated by the surface condition of the carrier. The criterion for a suitable formulation is always that the dry indicia should exhibit pre-release characteristic.

(b) The adhesive composition may be widely varied in respect of polyvinyl butyl ether and butyl acrylate/ methyl acrylate content to provide high and low tack adhesive, or any intermediate tack level. This will be dictated by the application in which the transfer is to be used.

EXAMPLE 2 A carrier sheet is employed which consists of a light transmitting film of biaxially oriented polystyrene having a high gloss surface and a caliper of .0015 inch and an elongation of 10%.

To this carrier sheet an indicia is applied consisting of cellulose nitrate polymer and plasticiser, to provide a clear transparent indicia; the additional incorporation of a pigment or dye produces a coloured indicia, the clear and coloured indicia having compositions in the following range:

Parts Cellulose nitrate (nitrogen content 10.5-11-2% 100 Plasticiser 20-150 Pigment or dye 0-200 The very high pigment concentration is used when really opaque indicia are required to obliterate the underlying receiving surface after transfer.

Typically a black indicia ink consists of:

Parts Cellulose nitrate 100 Castor oil modified glycerylsebacate 60 Dimethylcyclohexyladipate 14 Carbon black 20 A viscous solution of the above polymer and plasticiser in the following solvent is prepared:

Parts Isopropanol 43 Ethylene glycol monoethyl ether 350 and the pigment incorporated by triple roll milling and the ink is applied by screen process printing and dried by evaporation in a stream of warm air at 60 C. to give dry indicia with a thickness in the range of .0002 to .001 inch depending on the printing conditions. The indicia may be substantially freed by stretching the carrier sheet.

Additional colours may be applied to the same sheet as a further printing operation to give multicolour effects and indicia having numerous disconnected pieces may be tied together by printing clear indicia before or after the coloured indicia.

The solvents used in the above inks do not react with the carrier sheet even at the above elevated drying temperature, as shown by removing an indicia, e.g., with adhesive tape, and observing that there is no loss of gloss of the carrier film beneath the indicia compared to the unprinted adjacent film. A slight etching, i.e., seen as a semigloss finish on the carrier sheet, is acceptable particularly if it is desired to increase the mutual adhesion of indicia and carrier sheet, and this is achieved in the above ink compositions by replacing the ethylene glycol monoethyl ether by ethylene glycol monoethyl ether acetate.

To the carrier sheet and indicia, there is applied a tacky, cohesive and strong pressure sensitive adhesive having a composition in the following range:

Parts Elastomer Tackifying resin SO -800 Antioxidant 1-10 Parts Crepe rubber 100 Polymerised ,B-pinene 170 Dihydroabietyl phthalate Diamylhydroquinone 4 This adhesive is dissolved into the following solvent mixture, which is reactive with the carrier sheet at 80 C.:

Parts Aromatic hydrocarbon boiling range, l64-220 C.,

kauri-butanol value 90 500 Aliphatic hydrocarbon boiling range, 170-198 C.,

kauri-butanol value 35 400 to give a viscous liquid which is roller-coated to give a uniform coating and then dried in a stream of hot air at 90 C. to give a dry film of thickness, on the indicia, in the range of .0002-.0005 inch. A pronounced reaction between the overlapping adhesive and carrier sheet occurs during drying and is seen as a coarse matt finish on the dried sheet. If an element of indicia is now transferred, the contrast between the unreacted, glossy carrier film exactly beneath the indicia, and the surrounding reacted carrier film, is sharply visible.

To the above prepared transfer assembly, there is applied a protective cover sheet consisting of vegetable parchment paper sheet coated with methylhydrogen polysiloxane polymer in toluene solution containing a metallic salt catalyst which is dried and polymerised at C. for one minute to provide a non migratory and strongly adherent high release coating to the vegetable parchment sheet.

The plasticiser contents of the ink as noted above are to be regarded only as indicative of what is required. The formulation should be adjusted having regard to the surface condition of the carrier sheet to provide the indicated prerelease characteristics.

EXAMPLE 3 The carrier film used is a film of a polystyrene-butadiene copolymer. Indicia are screen-printed thereon from the following ink formulation.

Polyamide resin 80 parts by weight.

Plasomoll BMB Variable according to polymer surface condition and requirement of pre-release. Carbon black 5 parts by weight. Butyl alcohol 10 parts by weight.

Dispersed on triple roll mill.

An adhesive similar to that described in Example 2 is employed.

EXAMPLE 4 The carrier used is siliconised vegetable parchment. Indicia are screen-printed thereon in an ink which is a pigmented plasticised cellulose nitrate.

An adhesive is made by high speed mixing of the following ingredients:

Parts by weight Terpene resin emulsion (50% by weight solids in water) 37.3 Polyvinyl isobutyl ether (50% by weight solids in water) 37.3 Butyl acrylate/methyl methacrylate (50% by weight solids in water) 12.82 Methyl cellulose (50% by weight aqueous solution) 12.58

This adhesive is applied over the ink indicia and dried down.

After pre-release of the indicia the adhesive may be activated by spraying it with a mixture of equal volumes of xylene and ethyl acetate.

EXAMPLE The carrier is butadiene-modified polystyrene film. Indicia are screen printed thereon in an ink formulated as follows:

Parts by weight Polyamide resin (30% by weight solution in a mixture of equal volumes of furfuryl alcohol and butyl alcohol) 85 Carbon black 5 Furfuryl alcohol The ingredients of the ink are mixed and dispersed on a triple-roll mill.

An adhesive is made by high speed mixing of the following ingredients:

Parts by weight Polyvinyl isobutyl ether (50% by weight solids in water) 21.7 Cresylic resin (50% by weight solution in white spirit) 21.8 Emulsifying agent 0.5 Water 56 The adhesive is applied over the ink indicia and dried down.

After pie-release of the indicia the adhesive may be activated by the application of heat (7090 C. for preference) or by application of pressure.

As noted above it is a particular feature of the present invention to provide a tape dispenser charged with the transfer material of the present invention in the form of a reel of tape. In this form of the invention the indicia will usually be equally spaced along the length of the tape. In one form, the dispenser includes a bar or mandrel so located that as the tape is withdrawn from the reel it is pulled over the bar or mandrel and, in doing so, is caused to pass through a sharp angle. This angle is usually required to be of the order of a right angle. The effect, as noted is that, with the rear face of the carrier side of the tape adjacent the bar or mandrel, the indicia are successively released from the tape. In this condition they are free to be caused to adhere, by an adhesive, to any required receptor surface, e.g. where the adhesive is pressure-sensitive, by the application of a pressure which may, when the conditions are optimum, be only a very light pressure and therefore such as not to do any harm to the receptor surface. The carrier sheet of the tape then falls away. If there is an interleaved protective sheet (i.e., is interwound with the tape in the reel) this too falls away. It will be appreciated that the foregoing system is adapted to mechanisation so that tape of the transfer material fed from a reel, and pre-released as it leaves the dispenser, may have the successive indicia applied to successive receptor surfaces moving past a position in which a light pressure tool reciprocates to press each successive prereleased indicia onto successive receptor surfaces.

Instead of using a bar or mandrel as just described there may be employed a serrated surface and in that case it is sufiicient to ensure that the tape bears against said surface and not necessary that it should change direction through any substantial angle as it passes that surface.

Most conveniently the serrated surface may be provided by a bar carrying cylindrical or helical ridges and most conveniently by a bar carrying a screw thread. The pitch of the thread on the bar may be varied to suit the particular conditions, e.g. taking into account the peripheral contour of the apices of the thread and the amount of pressure between the threaded bar and the tape.

Suitable dispenser devices according to the present invention are illustrated in the accompanying drawings in which:

FIGURE 1 illustrates diagrammatically a dispenser adapted for manual operation;

FIGURE 2 illustrates diagrammatically a dispenser adapted for automatic operation.

Referring to FIGURE 1 the dispenser comprises a housing 1 having bearings 2 to carry a stock reel of transfer tape, guide rollers 3 and 4, a thin mandrel 5 and a guide bar 6. The tape 7 is withdrawn from the reel in the direction shown by the arrow and passes over rollers 3 and 4. If a protective paper is interwound with the tape this is led over the bar 6 to waste. The transfer tape itself passes round the mandrel 5 and in doing so indicia on it are pro-released. In this device the tape is pulled through manually and the pre-released indicia are located and adhered to receptor surfaces either manually or by the provision of pressing the tape onto the required receptor surface of any convenient mechanical means.

Referring to FIGURE 2 the housing 11 has bearings 12 to carry a stock reel of transfer tape, guide rollers 13 and 14, further guide rollers 15 and 16, a rewind reel 17, a mandrel 13, an application roll 19 and a further guide roll 29.

In operation of this device it is treated so that tape drawn from the stock reel passes over rollers 13 and 14 the backing paper passes over rollers 15 and 16 and hence to the rewind reel 17, while the transfer tape passes round the mandrel 18 (where the pre-release is effected) and then to the application roll 19 where pressure is applied against a receptor surface (not shown) so as to transfer the indicia. The tape then passes round guide roller 20 and is taken up by the rewind reel 17. The drive is effected by power supplied to the rewind reel and the necessary tension in the system is provided by the multiple directional changes which are involved.

In the foregoing device, for more accurate control of the pre-release, tension may be applied through the medium of an adjustable brake. Alternative means of drive may be applied, e.g. nip rollers at a suitable point in the traverse of the material.

For conveyorised labelling such a dispenser may have a vertical, reciprocating action with an indexing drive instead of continuous, both controlled correctly to locate the transfer on the articles. Alternatively a stamp may be used in place of a roller applicator. In all cases control may be exercised through mechanical, electromechanical, photoelectric or like devices according to which method is the more convenient in the specific application.

The indicia may be appliced to curved, grained or otherwise irregular surfaces by using resilient surfaced and/or shaped applicators, whether of roller or stamp design. Similarly, selection of tape width, type and design of applicator may allow for transferring into recesses.

The foregoing devices are intended essentially for use with transfer tapes which have a coating of pressuresensitive adhesive. Such a dispenser may include a source of infra-red radiation for use with tape carrying a heatsensitive adhesive, or may include a spray unit for solvent, or a solvent atmosphere, for use with tape carrying an adhesive which depends on solvent for its activation.

The process of the invention may be applied to the application of indicia to successive receptor surfaces of any type. It is particularly useful in the application of label indicia to containers, e.g. the application of label indicia to polythene bottles moving past the application station.

I claim as my invention:

1. A process for the application of indicia to successive receptor surfaces, which comprises withdrawing from a reel a transfer tape which consists essentially of a tape support carrying ink indicia successively printed along its length, the physical characteristics of the support and the ink being so mutually selected as to provide breaking of the bond between an indicium and the support without separating the indicium from the support by the action of dilferential stretching of indicium and support (e.g., by drawing the tape over an edge or surface of small radius with the rear face of the tape nearer to the said edge or surface and the front face carrying the indicia remote from that edge or surface, or by exerting tension in the tape support, or by a combination of any of these methods), breaking said bond by passing said tape over a structure producing such differential stretching but without separating said indicia from said support, and thereafter adhering the successive indicia to successive receptor surfaces.

2. A process according to claim 1 wherein the film support is a film of polyethylene or butadiene-modified polystyrene.

3. A process according to claim 1 wherein the tape support is a siliconised vegetable parchment.

4. A process according to claim 1 wherein the receptor surfaces carry adhesive for the indicia.

5. A process for the application of indicia to successive receptor surfaces, which comprises withdrawing from a reel a transfer tape which consists essentially of a tape support carrying ink indicia successively printed along its length, the physical characteristics of the support and the ink being so mutually selected as to provide breaking of the bond between an indicium and the support without separating the indicium from the support by the action of differential stretching of indicium and support (e.g. by drawing the tape over an edge or surface of small radius with the rear face of the tape nearer to the said edge or surface and the front face carrying the indicia remote from that edge or surface, or by exerting tension in the tape support, or by a combination of any of these methods), breaking said bond by passing said tape over a structure producing such dilferential stretching but without separating said indicia from said support, and thereafter adhering the successive indicia to successive receptor surfaces, the said tape carrying the adhesive for such adherence.

6. A process according to claim 5 wherein the adhesive is heat sensitive or solvent-activated and is included in the ink used for the indicia.

7. A process according to claim 5 wherein the adhesive is applied over the surface of the ink indicia.

8. A process according to claim 5 wherein the adhesive is a pressure sensitive adhesive.

9. A process for the application of indicia to successive receptor surfaces, which comprises withdrawing from a reel a transfer tape which consists essentially of a tape support carrying ink indicia successively printed along its length, the physical characteristics of the support and the ink being so mutually selected as to provide breaking of the bond between an indicium and the support by the action of differential stretching of indicium and support (e.g. by drawing the tape over an edge or surface of small radius with the rear face of the tape nearer to the said edge or surface and the front face carrying the indicia remote from that edge or surface, or by exerting tension in the tape support, or by a combination of any of these methods) the said indicia being carried with a pressure sensitive adhesive which overlaps onto the tape areas between the indicia, breaking said bond by passing said tape over a structure producing such differential stretching but without separating said indicia from said support, and thereafter adhering the successive indicia to successive receptor surfaces by means of the said adhesive.

10. A process according to claim 9 wherein the pressure sensitive adhesive is based on a mixture of a tacky ingredient and a deformable nontacking ingredient.

11. A process according to claim 9 wherein the adhesive is so fonnulated that it will shear round the periphery of an indicium on transfer of the indicium.

12. Apparatus for the application of indicia to receptor surfaces which comprises means for holding a reel of transfer tape having indicia carried on a tape support, means for withdrawing tape from the reel and means associated therewith for differentially stretching said indicia and support to break the bond between said indicia and support without separating said indicia from said support, and means for thereafter adhering said indicia to a said receptor surface including means for applying pressure to the face of said support opposite from the face carrying said indicia.

13. A process according to claim 7, further including the step of thereafter transferring said indicium from said support to a said receptor surface by applying pressure to said support opposite to the location of said indicium.

References Cited UNITED STATES PATENTS 3,131,106 4/1964 Mackenzie 156230 3,169,895 2/1965 Sohn 156--361 3,222,242 12/1965 Ingalls et al. 156584 3,321,105 5/1965 Marano 221-22 HAROLD ANSHER, Primary Examiner J. D. SMITH, Assistant Examiner U.S. Cl. X.R. 156-240, 542 

